A typical telecommunication network comprises terminal equipment, switching machines, and transmission lines, usually distributed over a wide geographical area. Before the aforesaid network can be used efficiently, it is necessary to know with precision how the component parts are connected.
A network grows by the incremental addition of the aforesaid terminal equipment, switching machines and transmission lines. The hard-wired interconnections between the aforesaid components are constantly being rearranged to take account of changes in traffic patterns and to overcome problems caused by defective equipment.
Consequently, there is a danger that over a period of time no accurate record of network configuration will be kept when manual record keeping is used. Furthermore, the aforesaid rearrangements and record keeping errors accumulate with time; it is not easy to determine by inspection how the component parts of the distributed network are interconnected.